Fix incorrect use of clz (#8)

* fix incorrect use of clz when input is 0
* don't force use of native arch when building

Author: bignacio

simple_pool/CMakeLists.txt

@@ -19,7 +19,6 @@ add_compile_options(
     -Wimplicit-fallthrough
     -Wundef
     -Wfloat-equal
-    -march=native
     -fPIE
     -fno-omit-frame-pointer
 )

simple_pool/dyn_mem_pool.h

@@ -313,6 +313,9 @@ void multipool_free(struct MultiPool* multipool) {
 uint32_t find_multipool_index_for_size(uint32_t size) {
     static const uint32_t int32bitcount = sizeof(uint32_t) * CHAR_BIT;
     uint32_t size_value = (size - 1) >>DynPoolMinMultiPoolMemNodeSizeBits;
+    if( __builtin_expect(size_value == 0, 0)) {
+        return 0;
+    }
     return (int32bitcount - (uint32_t)__builtin_clz(size_value));
 }